Cloning and sequencing of the Klebsiella K-36 astA gene, encoding an arylsulfate sulfotransferase

Abstract

A gene-encoding arylsulfate sulfotransferase (ASST) was cloned from a Klebsiella K-36 genomic library. ASST transfers a sulfate group from phenolic sulfate esters to a phenolic acceptor substrate. The gene, designated astA, was subcloned into vector pGEM3Zf(-) and sequenced. Recombinant clone-harbouring astA was directly identified using a fluorescent product. The nucleotide sequencing revealed an open reading frame (ORF) of 2,082 bp encoding a protein of 694 amino acids with a secretory signal sequence. A protein of similar size was visualized after in vitro transcription and translation using a plasmid carrying the cloned 3.1-kb fragment as a template. The N-terminal amino acid sequence of the purified processed protein was found to be identical to that predicted from the gene sequence. When searching the database for astA nucleotide or its deduced amino acid sequence, no significant homology to any sequence was found.